ssl/packet.c

   1 /*
   2  * Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <assert.h>
  11 #include "packet_locl.h"
  12
  13 #define DEFAULT_BUF_SIZE    256
  14
  15 int WPACKET_allocate_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)
  16 {
  17     if (!WPACKET_reserve_bytes(pkt, len, allocbytes))
  18         return 0;
  19
  20     pkt->written += len;
  21     pkt->curr += len;
  22     return 1;
  23 }
  24
  25 int WPACKET_sub_allocate_bytes__(WPACKET *pkt, size_t len,
  26                                  unsigned char **allocbytes, size_t lenbytes)
  27 {
  28     if (!WPACKET_start_sub_packet_len__(pkt, lenbytes)
  29             || !WPACKET_allocate_bytes(pkt, len, allocbytes)
  30             || !WPACKET_close(pkt))
  31         return 0;
  32
  33     return 1;
  34 }
  35
  36 #define GETBUF(p)   (((p)->staticbuf != NULL) \
  37                      ? (p)->staticbuf : (unsigned char *)(p)->buf->data)
  38
  39 int WPACKET_reserve_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)
  40 {
  41     /* Internal API, so should not fail */
  42     assert(pkt->subs != NULL && len != 0);
  43     if (pkt->subs == NULL || len == 0)
  44         return 0;
  45
  46     if (pkt->maxsize - pkt->written < len)
  47         return 0;
  48
  49     if (pkt->staticbuf == NULL && (pkt->buf->length - pkt->written < len)) {
  50         size_t newlen;
  51         size_t reflen;
  52
  53         reflen = (len > pkt->buf->length) ? len : pkt->buf->length;
  54
  55         if (reflen > SIZE_MAX / 2) {
  56             newlen = SIZE_MAX;
  57         } else {
  58             newlen = reflen * 2;
  59             if (newlen < DEFAULT_BUF_SIZE)
  60                 newlen = DEFAULT_BUF_SIZE;
  61         }
  62         if (BUF_MEM_grow(pkt->buf, newlen) == 0)
  63             return 0;
  64     }
  65     if (allocbytes != NULL)
  66         *allocbytes = WPACKET_get_curr(pkt);
  67
  68     return 1;
  69 }
  70
  71 int WPACKET_sub_reserve_bytes__(WPACKET *pkt, size_t len,
  72                                 unsigned char **allocbytes, size_t lenbytes)
  73 {
  74     if (!WPACKET_reserve_bytes(pkt, lenbytes + len, allocbytes))
  75         return 0;
  76
  77     *allocbytes += lenbytes;
  78
  79     return 1;
  80 }
  81
  82 static size_t maxmaxsize(size_t lenbytes)
  83 {
  84     if (lenbytes >= sizeof(size_t) || lenbytes == 0)
  85         return SIZE_MAX;
  86
  87     return ((size_t)1 << (lenbytes * 8)) - 1 + lenbytes;
  88 }
  89
  90 static int wpacket_intern_init_len(WPACKET *pkt, size_t lenbytes)
  91 {
  92     unsigned char *lenchars;
  93
  94     pkt->curr = 0;
  95     pkt->written = 0;
  96
  97     pkt->subs = OPENSSL_zalloc(sizeof(*pkt->subs));
  98     if (pkt->subs == NULL)
  99         return 0;
 100
 101     if (lenbytes == 0)
 102         return 1;
 103
 104     pkt->subs->pwritten = lenbytes;
 105     pkt->subs->lenbytes = lenbytes;
 106
 107     if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars)) {
 108         OPENSSL_free(pkt->subs);
 109         pkt->subs = NULL;
 110         return 0;
 111     }
 112     pkt->subs->packet_len = lenchars - GETBUF(pkt);
 113
 114     return 1;
 115 }
 116
 117 int WPACKET_init_static_len(WPACKET *pkt, unsigned char *buf, size_t len,
 118                             size_t lenbytes)
 119 {
 120     size_t max = maxmaxsize(lenbytes);
 121
 122     /* Internal API, so should not fail */
 123     assert(buf != NULL && len > 0);
 124     if (buf == NULL || len == 0)
 125         return 0;
 126
 127     pkt->staticbuf = buf;
 128     pkt->buf = NULL;
 129     pkt->maxsize = (max < len) ? max : len;
 130
 131     return wpacket_intern_init_len(pkt, lenbytes);
 132 }
 133
 134 int WPACKET_init_len(WPACKET *pkt, BUF_MEM *buf, size_t lenbytes)
 135 {
 136     /* Internal API, so should not fail */
 137     assert(buf != NULL);
 138     if (buf == NULL)
 139         return 0;
 140
 141     pkt->staticbuf = NULL;
 142     pkt->buf = buf;
 143     pkt->maxsize = maxmaxsize(lenbytes);
 144
 145     return wpacket_intern_init_len(pkt, lenbytes);
 146 }
 147
 148 int WPACKET_init(WPACKET *pkt, BUF_MEM *buf)
 149 {
 150     return WPACKET_init_len(pkt, buf, 0);
 151 }
 152
 153 int WPACKET_set_flags(WPACKET *pkt, unsigned int flags)
 154 {
 155     /* Internal API, so should not fail */
 156     assert(pkt->subs != NULL);
 157     if (pkt->subs == NULL)
 158         return 0;
 159
 160     pkt->subs->flags = flags;
 161
 162     return 1;
 163 }
 164
 165 /* Store the |value| of length |len| at location |data| */
 166 static int put_value(unsigned char *data, size_t value, size_t len)
 167 {
 168     for (data += len - 1; len > 0; len--) {
 169         *data = (unsigned char)(value & 0xff);
 170         data--;
 171         value >>= 8;
 172     }
 173
 174     /* Check whether we could fit the value in the assigned number of bytes */
 175     if (value > 0)
 176         return 0;
 177
 178     return 1;
 179 }
 180
 181
 182 /*
 183  * Internal helper function used by WPACKET_close() and WPACKET_finish() to
 184  * close a sub-packet and write out its length if necessary.
 185  */
 186 static int wpacket_intern_close(WPACKET *pkt)
 187 {
 188     WPACKET_SUB *sub = pkt->subs;
 189     size_t packlen = pkt->written - sub->pwritten;
 190
 191     if (packlen == 0
 192             && (sub->flags & WPACKET_FLAGS_NON_ZERO_LENGTH) != 0)
 193         return 0;
 194
 195     if (packlen == 0
 196             && sub->flags & WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH) {
 197         /* Deallocate any bytes allocated for the length of the WPACKET */
 198         if ((pkt->curr - sub->lenbytes) == sub->packet_len) {
 199             pkt->written -= sub->lenbytes;
 200             pkt->curr -= sub->lenbytes;
 201         }
 202
 203         /* Don't write out the packet length */
 204         sub->packet_len = 0;
 205         sub->lenbytes = 0;
 206     }
 207
 208     /* Write out the WPACKET length if needed */
 209     if (sub->lenbytes > 0
 210                 && !put_value(&GETBUF(pkt)[sub->packet_len], packlen,
 211                               sub->lenbytes))
 212             return 0;
 213
 214     pkt->subs = sub->parent;
 215     OPENSSL_free(sub);
 216
 217     return 1;
 218 }
 219
 220 int WPACKET_close(WPACKET *pkt)
 221 {
 222     /*
 223      * Internal API, so should not fail - but we do negative testing of this
 224      * so no assert (otherwise the tests fail)
 225      */
 226     if (pkt->subs == NULL || pkt->subs->parent == NULL)
 227         return 0;
 228
 229     return wpacket_intern_close(pkt);
 230 }
 231
 232 int WPACKET_finish(WPACKET *pkt)
 233 {
 234     int ret;
 235
 236     /*
 237      * Internal API, so should not fail - but we do negative testing of this
 238      * so no assert (otherwise the tests fail)
 239      */
 240     if (pkt->subs == NULL || pkt->subs->parent != NULL)
 241         return 0;
 242
 243     ret = wpacket_intern_close(pkt);
 244     if (ret) {
 245         OPENSSL_free(pkt->subs);
 246         pkt->subs = NULL;
 247     }
 248
 249     return ret;
 250 }
 251
 252 int WPACKET_start_sub_packet_len__(WPACKET *pkt, size_t lenbytes)
 253 {
 254     WPACKET_SUB *sub;
 255     unsigned char *lenchars;
 256
 257     /* Internal API, so should not fail */
 258     assert(pkt->subs != NULL);
 259     if (pkt->subs == NULL)
 260         return 0;
 261
 262     sub = OPENSSL_zalloc(sizeof(*sub));
 263     if (sub == NULL)
 264         return 0;
 265
 266     sub->parent = pkt->subs;
 267     pkt->subs = sub;
 268     sub->pwritten = pkt->written + lenbytes;
 269     sub->lenbytes = lenbytes;
 270
 271     if (lenbytes == 0) {
 272         sub->packet_len = 0;
 273         return 1;
 274     }
 275
 276     if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars))
 277         return 0;
 278     /* Convert to an offset in case the underlying BUF_MEM gets realloc'd */
 279     sub->packet_len = lenchars - GETBUF(pkt);
 280
 281     return 1;
 282 }
 283
 284 int WPACKET_start_sub_packet(WPACKET *pkt)
 285 {
 286     return WPACKET_start_sub_packet_len__(pkt, 0);
 287 }
 288
 289 int WPACKET_put_bytes__(WPACKET *pkt, unsigned int val, size_t size)
 290 {
 291     unsigned char *data;
 292
 293     /* Internal API, so should not fail */
 294     assert(size <= sizeof(unsigned int));
 295
 296     if (size > sizeof(unsigned int)
 297             || !WPACKET_allocate_bytes(pkt, size, &data)
 298             || !put_value(data, val, size))
 299         return 0;
 300
 301     return 1;
 302 }
 303
 304 int WPACKET_set_max_size(WPACKET *pkt, size_t maxsize)
 305 {
 306     WPACKET_SUB *sub;
 307     size_t lenbytes;
 308
 309     /* Internal API, so should not fail */
 310     assert(pkt->subs != NULL);
 311     if (pkt->subs == NULL)
 312         return 0;
 313
 314     /* Find the WPACKET_SUB for the top level */
 315     for (sub = pkt->subs; sub->parent != NULL; sub = sub->parent)
 316         continue;
 317
 318     lenbytes = sub->lenbytes;
 319     if (lenbytes == 0)
 320         lenbytes = sizeof(pkt->maxsize);
 321
 322     if (maxmaxsize(lenbytes) < maxsize || maxsize < pkt->written)
 323         return 0;
 324
 325     pkt->maxsize = maxsize;
 326
 327     return 1;
 328 }
 329
 330 int WPACKET_memcpy(WPACKET *pkt, const void *src, size_t len)
 331 {
 332     unsigned char *dest;
 333
 334     if (len == 0)
 335         return 1;
 336
 337     if (!WPACKET_allocate_bytes(pkt, len, &dest))
 338         return 0;
 339
 340     memcpy(dest, src, len);
 341
 342     return 1;
 343 }
 344
 345 int WPACKET_sub_memcpy__(WPACKET *pkt, const void *src, size_t len,
 346                          size_t lenbytes)
 347 {
 348     if (!WPACKET_start_sub_packet_len__(pkt, lenbytes)
 349             || !WPACKET_memcpy(pkt, src, len)
 350             || !WPACKET_close(pkt))
 351         return 0;
 352
 353     return 1;
 354 }
 355
 356 int WPACKET_get_total_written(WPACKET *pkt, size_t *written)
 357 {
 358     /* Internal API, so should not fail */
 359     assert(written != NULL);
 360     if (written == NULL)
 361         return 0;
 362
 363     *written = pkt->written;
 364
 365     return 1;
 366 }
 367
 368 int WPACKET_get_length(WPACKET *pkt, size_t *len)
 369 {
 370     /* Internal API, so should not fail */
 371     assert(pkt->subs != NULL && len != NULL);
 372     if (pkt->subs == NULL || len == NULL)
 373         return 0;
 374
 375     *len = pkt->written - pkt->subs->pwritten;
 376
 377     return 1;
 378 }
 379
 380 unsigned char *WPACKET_get_curr(WPACKET *pkt)
 381 {
 382     return GETBUF(pkt) + pkt->curr;
 383 }
 384
 385 void WPACKET_cleanup(WPACKET *pkt)
 386 {
 387     WPACKET_SUB *sub, *parent;
 388
 389     for (sub = pkt->subs; sub != NULL; sub = parent) {
 390         parent = sub->parent;
 391         OPENSSL_free(sub);
 392     }
 393     pkt->subs = NULL;
 394 }